AirSpaceMag.com

Tumbling with the Stars

Today’s airshow performers do it gyroscopically.

Head games: Fierce concentration is what keeps airshow pilot Greg Poe from knocking his noggin during a low inverted pass. With equal focus, Poe and other aerobatic pilots control their aircraft even during the most chaotic tumbles.
(Courtesy Greg Poe Airshows)

When I started flying airshows, back in 1971, the edge of the known aerobatic world was a maneuver known as the lomcevak. The great-granddaddy of tumbles, the lomcevak (pronounced “LAHM-sha-vock”) took you to a wild place, where one minute the air under your wing was solid as a fist, and the next you were toppling tailwheel over nose cone into the abyss, as out of control as an unhinged car on a Ferris wheel.

From This Story

What does it take to be a top airshow performer? Talent, of course, and the ability to withstand physically demanding maneuvers at 250 miles per hour. But it also takes lots of practice, as Sean D. Tucker of Team Oracle demonstrates in this exclusive video showing one of his 800-times-a-year practice sessions. Over the Michigan countryside, Tucker flies a routine that includes rolls, loops, and a generous helping of smoke.

SHOULDER ROLL
When the maneuver is flown in competition, the flight path is a parabolic curve. If the airplane enters the maneuver upright and with the nose pointed
about 45 degrees to the right of the direction of flight, the nose will point
back to the original heading when the airplane rolls inverted. As the airplane completes the roll, the nose is pointed 45 degrees to the left of the direction
of flight.
(Illustration by Harry Whitver)

VERTICAL ROLL
Throughout a vertical roll, a standard airshow maneuver, the aircraft’s nose points straight up. In a negative vertical snap roll, which Nicolay Timofeev’s friends were flying, the nose would describe an upward spiral and the pilot would experience negative G, which would push him forward against his seat belts.
(Illustration by Harry Whitver)

KNIFE-EDGE SPIN
Imagine an airplane with its right wing pointed at the ground and its left at the sky. As the plane rotates, the right, or lower, wing will describe a smaller radius than the left. Its smoke trail will spiral like a telephone cord.
(Illustration by Harry Whitver)

Famous for inventiveness, Tucker has a new act: flying formation with his son.
(Tyson Rininger)

Aerobatic champ Michael Goulian lets his fingers do the tumbling — in a typical show pilot rehearsal — before climbing into his Extra 300SHP, powered by a Lycoming Thunderbolt engine.
(Tyson Rininger)

Recently I watched aerobatic performer Greg Poe cartwheel his bright red Fagen MX-2 across the show line. A few beats later, the airplane began a tight, fast, vertical roll, which widened into a corkscrew and topped out around 2,000 feet. There it stayed, continuing to rotate, but now Frisbee-like, with its nose following the horizon. It hovered for a moment before flat spinning downward. Poe had seamlessly blended four maneuvers into a single magic trick. His routine is only one of a dozen on the airshow circuit today that make me realize: Tumbles have changed.

Nobody knows exactly how many kinds of tumbles there are now. If we could tally all the differences in the maneuvers that depend on aircraft design, center of gravity, entry and exit attitudes, control movements that change during the maneuvers, and the amount of experience and recent practice pilots have, the number would be overwhelming. Some show pilots have created—and named—signature tumbles. One of the most famous is Sean Tucker’s Centrifuge. Tucker’s Oracle Challenger Pitts leaps across the sky from tumble to tumble. Its nose twists over its right shoulder toward its tail 7, 8, 9 times—as if snarling at a demon behind it—10, 11, 12 times.

All the various tumbles have one thing in common: Pilots get into them by using the gyroscopic effect of a spinning propeller. Pushing on a spinning gyro moves it 90 degrees to the left or right of the direction the push came from. A pilot starts a roll, and, with the help of the propeller’s gyroscopic forces, skids the nose to point at an angle from the line of forward motion (see “Shoulder Roll,” opposite). The airplane behaves like a car going downhill fast, skidding sideways, then rolling over.

When the only game in town was the lomcevak, we entered the tumble in climbing roll, pushed the ailerons on our wings one way and the rudder on our tail the other way, then just hung on until the airplane spit us out into an inverted spin. The airplanes responded differently. For instance, my Pitts would tumble slightly cock-eyed, tail over wing, whereas Art Scholl’s Super Chipmunk would tumble forward, tail following nose as if the airplane were inside a squirrel cage. But we called them all lomcevaks—a Czech word for either a headache, a hangover, or a big slug of plum brandy; we’d heard all these translations.

We did them on purpose, of course, but three-time world aerobatic pilot Nikolay Timofeev says that Czech pilot Ladislav Bezak probably discovered the first one in his Zlin by accident, the way Soviet pilots discovered some of their tumbling maneuvers around 1976. “As soon as we receive Yak 50 we start to do negative snaps on vertical line,” he says (see “Vertical Roll,” left). “And we jump into gyroscopic inertia rotation because Yak 50 is not really good airplane for negative snaps, especially on vertical up lines. I believe same story in Czech Republic. Zlin 50 is also not excellent for negative snap on way up.”

Mistakes can be turned into maneuvers if pilots can figure out what they did in the first place. Former U.S. national aerobatic champion David Martin has perfected a forward tumble that is so straight and so tightly flown that it looks as if his CAP 232 is swinging by its tailwheel from a high wire. He has spent thousands of hours practicing aerobatics, particularly his tumbles.

“If you are talking something new that you want to do in an airshow,” he says, “you have to figure out how to do it; then you have to figure out how to consistently do it; then you’ve got to figure out doing it at a lower altitude. It takes a while. I practice purposely messing them up. Because if I am going to be doing them at low altitude, I need to know what is going to happen. So that is a lot of practice.”
The first time he did the one he calls the Good Tumble it was by accident, but luckily someone got it on video. “I looked at that video hundreds of times, trying to figure out exactly what I did,” he says. “It took a long time. At first, even after I figured out how to do it, I might get it 50 percent of the time, then it would be 75 percent, then finally I’ve got it now where it is. I won’t say it is 100 percent, but at least 90 percent of the time it will do what I want it to do.

“The thing I learned about tumbling maneuvers is that nobody is very good at telling you how to do it. You’ve got to kind of figure it out on your own.”

Debby Rihn-Harvey, the current national aerobatic champion, says that when airshow fans ask about tumbles, pilots are cautious about what they share, because tumbles are potentially dangerous. “Every airplane is going to be a little bit different,” she says.
Rihn-Harvey flies a CAP 232 she calls the Hurricane II. Her show routine includes about six types of tumbles that she flies with competition-style precision and a touch of Texas yeehaw. When she’s not flying shows, Rihn-Harvey is an airline pilot and has her own flight school: H&R Aviation, in La Porte, Texas; if a stranger walks up and says, “How do you do that?” she says, “Come see me.”